NEWTON : CONCHOLOGICAL FEATURES OF LENHAM SANDSTONES. I39 



Panop^ea menardi Deshayes. 

 Fig. g. — Left lateral aspect of specimen with parts (dorsal region) of 

 both valves in the closed condition, showing the elongately 

 concentric growth lines and obscure evidence of irregular 

 radial striations. From a gutta-percha model. 



[M.P.G., No. 428]. 

 Cyrtodaria angusta Nyst and Westendorp, sp. 

 Fig. 10. — Left lateral view of specimen with both valves in the closed 

 state, preserved as a natural sandstone cast. The valves 

 are very compressed and posteriorly produced. 



[B.M., No. L., 24065]. 

 AspiDOPHOLAS rugosa Brocchi, sp. 

 Fig. II. — External view of a left valve with traces of the umbono- 

 ventral suture dividing it into two parts. From a gutta- 

 percha cast. [M.P.G., not numbered]. 



PLATE 2. 



Pelecypoda (extinct). 



Tapes perovalis S. V. Wood. 

 Fig. I. — Lateral view of a left valve with elongately oval contour and 

 distant concentric growth lines. From a gutta-percha model. 



[M.P.G., No. 434]- 

 AsTARTE galeottii Nyst. 

 Fig. 2. — A fragmentary left valve, showing the numerous close con- 

 centric costse of this species. From a wax impression x 2. 



[B.M., Graham Wallas Coll.]. 

 AsTARTE omalii Lajonkaire. 

 Fig. J. — Lateral aspect of a left valve, showing an ovate trigonal con- 

 tour, strong concentric ridges, and a sub-angulate posterior 

 margin. From a gutta-percha model x 2. 



[M.P.G., No. 416]. 

 AsTARTE BASTEROTi Lajonkaire. 

 Fi^. ^. — External aspect of a right valve in which the concentric 

 costae are more prominent over the umbonal surface than 

 elsewhere. 

 Fig. 5. — An enlarged figure of the same specimen x 2|. 



From a wax impression. [B.M., Graham Wallas Coll.]. 



ASTARTE MUTABILIS S. V. Wood. 



Fig. 6. — Right lateral view of specimen with closed valves, furnished 

 with distant growth lines, and possessing a nearly horizontal 

 ventral margin. 



